Polytene chromosomes normal.
Amino acid replacement: R?H. The amino acid replacement is at a phosphate contacting Arginine residue within the second zinc finger of the DNA binding domain.
Missense mutation in the DNA-binding domain.
Nucleotide substitution: G?A. Amino acid replacement: R160H. Mutation is in the conserved arginine residues in the DNA binding domain (DBD).
G2040435A
R160H | usp-PA; R160H | usp-PB
R160H
adult mushroom body & axon
antennal lobe & axon
dorsal mesothoracic disc & neuron | somatic clone
gamma-lobe & neuron | somatic clone
olfactory neuron & axon
olfactory neuron & dendrite
Homozygous ddaC dendritic arborisation neuron MARCM clones do not show dendrite branching defects.
usp3 somatic C4da neuron clones fail to prune their larval dendrites at 20 hours after pupal formation, with approximately 90% of large dendritic branches being retained after head eversion.
At the the wandering third instar stage, persistent olfactory projection neurons (PPNs) exhibit normal morphology. However, 8 hours APF significant defects in dendrite and axon pruning are observed. In the majority of cases, both dendritic densities in the location of the larval antennal lobe and exon branches in the mushroom body (MB) calyx are retained. In the adult fly mutant PPNs generally appear to target appropriate glomeruli in the adult antennal lobe (AL); however ectopic processes in additional areas of the AL, which may be persisting larval dendrites, are often present. In a few cases mutant PPN dendrites are sparser and less specifically targetted to particular glomeruli, but still remain somewhat confined to certain regions of the AL. About 40% of mutant PPNs retain larval-like boutons directly on their main trunks in the mushroom body calyx; however they always have side branches with terminal branches as well. In addition the main axon trunk often diverts from the inner antennocerebral tract in the MB calyx. Nearly all mutant PPN axons exhibit grossly wild-type morphologies in the adult lateral horn (LH).
The disappearance of varicosities and the increase in axon disconnections which are seen in wild-type γ mushroom body neurons during early pupal stages are significantly suppressed in usp3 animals.
In larval brains usp3 homozygous mutant γ neurons acquire axonal and dendritic projections indistinguishable from wild-type. However during metamorphosis, pruning of larval dendrites and axons is not observed in usp3 mutant single cell or two cell clones. All mutant γ neurons retain their larval-type bifurcation of axons into the adult stage.
usp3/Y larvae arrested during the first larval instar stage have both first and second larval instar mouth hooks.
Homozygous clones in the margin region of the wing disc show precocious differentiation of neurons.
Heterozygotes are viable and fertile. Ovaries of heterozygous females develop almost normally. The number of ovarioles, the number of terminal filament (TF) cells/stack and ovary size are normal and epithelial sheath morphogenesis occurs normally. There is a significant increase in the number of TF cells formed at 24 hours after ecdysis to the third instar relative to control flies. Large homozygous clones in the ovary result in regions lacking TFs which appear undifferentiated. Smaller clones in the anterior of the ovary result in abnormal TF formation either when several contiguous cells within a TF stack are homozygous for usp3 or when TF stacks are surrounded by predominantly homozygous usp3 cells. Mosaic ovaries have fewer TF stacks formed at the onset of metamorphosis than control flies.
Homozygous clones in the eye imaginal disc that lie posterior to the morphogenetic furrow have an abnormal arrangement of developing photoreceptor clusters. The clusters are irregularly spaced and differentiate prematurely, although they contain the normal number of cells. Movement of the morphogenetic furrow is accelerated where it passes through a homozygous clone. This displacement of the furrow is not caused by excess proliferation of usp3 cells in the clone.
Heterozygotes display thoracic defects ranging from mild, slight separation of the microchaetes and macrochaetes along the dorsal midline, to severe, a cleft extending through both the notum and scutellum. Flies also have bent and misshapen sensory bristles and develop severely knarled legs.
usp3 clones in the head show two distinct morphological abnormalities: usp3 retinas contain enlarged, split rhabdomeres, which wrap around the cell body. They only extend into the outside 20% of the retina. The ventral third of the retina is often atrophic and thinner than the dorsal part of the retina in eyes with usp3 clones. This phenotype is correlated with the presence of a usp3 clone in the eye-antennal disc, but not with the presence of a usp3 clone in the retina, and is a non-autonomous phenotype. Most of the eggs laid by usp3 mosaic females mutant in the germline are fertilised.
Phenotype of homozygous germ line clones is maternal effect lethal.
Homozygous usp3 germline generates misshapen eggs that are unfertilized with fused filaments.
usp3 has lethal | larval stage phenotype, suppressible by usp::Cten\Usp-1d-c
Df(2R)nap11, usp3 has partially lethal | dominant phenotype
EcRM554fs, usp3 has terminal filament phenotype
EcRM554fs, usp3 has ovarian sheath phenotype
Df(2R)nap11, usp3 has ovary phenotype
Df(2R)nap11, usp3 has terminal filament phenotype
Df(2R)nap11, usp3 has ovarian sheath phenotype
usp3; Df(2R)nap11 double heterozygotes have reduced viability; approximately 10% of these flies arrest at head eversion and less than 10% differentiate and either fail to eclose or die during eclosion. The majority of flies that eclose are fertile. Ovary defects seen in these double mutant flies, but not seen in either single mutant heterozygote include reduced numbers of TFs at pupariation, fused adjacent TFs, drastically reduced apical cell populations, severe epithelial sheath defects and two "heterochronic shift" phenotypes. The first heterochronic shift phenotype is a delay in completion of TF formation, which is correlated with a delay in the onset of TF formation in the final larval stage. The second heterochronic shift phenotype is asymmetric ovarian growth, which is seen in 8% of double heterozygotes. usp3; EcRM554fs double heterozygotes show a range of ovary defects including apical cell, TF cell and epithelial cell defects and reduced ovary size.
Mutant larvae rescued by one copy of usp::Cten\Usp-1d-c die at the late third instar stage. Rescued usp3 mutants show a cessation of movement during the late third instar, but larvae show no sign of prepupal tanning except along the denticle belts of the midsegments. The addition of a second copy of usp::Cten\Usp-1d-c leads to further tanning of larvae, but they continue to fail to undergo pupal contraction, and anterior spiracle eversion is incomplete. The addition of three and four copies does allow some adults to survive.
Clonal analysis indicates that usp has a cell non-autonomous effect on terminal filament differentiation.
Maternal germline clonal analysis demonstrates a maternal effect lethal phenotype, defects in most posterior segments, is rescuable.
No interaction with P{sev-svp1} or P{sev-svp2} exists.